Apparatus and method for deploying stent across adjacent tissue layers

ABSTRACT

Transluminal access system includes a stent delivery catheter having a handle control mechanism. The catheter comprises a number of components for establishing an initial penetration between adjacent body lumens and subsequently implanting a stent or other luminal anchor therebetween. Manipulation of the stent components is achieved using control mechanisms on the handle while the handle is attached to an endoscope which provides access to a first body lumen.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of provisional application No.61/182,312, filed on May 29, 2009, the full disclosure of which isincorporated herein by reference. The disclosure of the presentapplication is related to those of commonly owned copending applicationSer. Nos. 12/427,215, filed on Apr. 21, 2009; 12/757,408, filed on Apr.9, 2010, and 12/757,421, filed on Apr. 9, 2010, the full disclosures ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical devices and methods.More particularly, the present invention relates to inter-luminal stentsand anchors as well as catheters and methods for their deployment.

A number of inter-luminal endoscopic procedures require preciseplacement of tissue anchors or stents. For example, a number ofprocedures may be performed by entering the gastrointestinal (GI) tractthrough a first organ or structure, such as the esophagus, stomach,duodenum, small intestine, or large intestine, and delivering the anchoror stent to adjacent organs and structures such as the bile duct, thepancreatic duct, the gallbladder, the pancreas, cysts, pseudocysts,abscesses, and the like.

Such endoscopic procedures often require the delivery of a tissue anchoror stent to secure adjacent tissues or organs and optionally to providean opening therebetween. Inter-luminal tissue anchors, typicallyreferred to as stents when they include a central lumen, are used toenable fluid communication between adjacent ducts, organs or lumens.Often, precise placement of the tissue anchor or stent is necessary,especially when the tissue anchor or stent has well defined anchoringelements at the proximal and/or distal ends, the device is used tosecure adjacent lumens, or the device is placed within a duct at aprecise location and secured at the proximal and/or distal ends.

When deploying a stent or other tissue anchor between adjacent bodylumens, organs, or other structures, it is typically necessary topenetrate a wall of both the first body lumen through which access isestablished and a wall of a second body lumen which is the target of theprocedure. When initially forming such access penetrations, there issignificant risk of leakage from either the access body lumen or organ.In some cases, such as when accessing the bile duct, loss of the bodyfluid into surrounding tissues and body cavities can present substantialrisk to the patient. Thus, it would be desirable to be able to establishthe initial penetrations needed to deploy a stent or anchor whileminimizing the risk of body fluid leakage. The risk of body fluidleakage can be exacerbated when multiple catheters or other tools areneeded for placement of the stent or other anchor. In particular, theneed to exchange tools over a guidewire or through an access cathetercan both prolong the procedure and increase the risk of body fluidleakage during the procedure.

Thus, it would be desirable to minimize both the time and the number oftools which are needed when endoscopically placing stents or otheranchors between adjacent body lumens or organs.

It would be further desirable to provide catheters and access toolswhich are capable of being deployed from endoscopes to access adjacentbody lumens or cavities while minimizing the risk of leakage. It wouldbe particularly desirable to provide catheters and tools which includeall elements and capabilities needed to both penetrate the luminal wallsand place the stent or other anchor between said walls, thus eliminatingthe need to exchange tools during an access procedure. It would be stillfurther desirable if such tools and access methods could continuallyapply tension on the luminal walls to maintain said walls in closeapposition during the stent or other anchor placement, thus furtherreducing the risk of body fluid loss during the procedure prior to finaldeployment of the stent or other tissue anchor. At least some of theseobjectives will be met by the inventions described below.

2. Description of the Background Art

US2009/0281379 and US2009/0281557 describe stents and other tissueanchors of the type that can be deployed by the apparatus and methods ofthe present invention. The full disclosures of these publications areincorporated herein by reference. US 2003/069533 describes an endoscopictransduodenal biliary drainage system which is introduced through apenetration, made by a trans-orally advanced catheter having a needlewhich is advanced from the duodenum into the gallbladder. U.S. Pat. No.6,620,122 describes a system for placing a self-expanding stent from thestomach into a pseudocyst using a needle and an endoscope. US2005/0228413, commonly assigned with the present application, describesa tissue-penetrating device for endoscopy or endosonography-guided(ultrasonic) procedures where an anchor may be placed to form ananastomosis between body lumens, including the intestine, stomach, andgallbladder. See also U.S. Pat. No. 5,458,131; U.S. Pat. No. 5,495,851;U.S. Pat. No. 5,944,738; U.S. Pat. No. 6,007,522; U.S. Pat. No.6,231,587; U.S. Pat. No. 6,655,386; U.S. Pat. No. 7,273,451; U.S. Pat.No. 7,309,341; US 2004/0243122; US 2004/0249985; US 2007/0123917; WO2006/062996; EP 1314404 Kahaleh et al. (2006) Gastrointestinal Endoscopy64:52-59; and Kwan et al. (2007) Gastrointestinal Endoscopy 66:582-586.Shaped balloons having differently sized segments and segments withstaged opening pressures are described in U.S. Pat. Nos. 6,835,189;6,488,653; 6,290,485; 6,022,359; 5,843,116; 5,620,457; 4,990,139; and3,970,090.

SUMMARY OF THE INVENTION

The present invention provides methods and apparatus for establishingtransluminal access between a first body lumen and a second body lumen.Such transluminal access may be intended for any medical purpose butwill usually be intended for performing transluminal therapeuticendoscopy where the first body lumen is typically within thegastrointestinal (GI) tract, including the esophagus, the stomach, theduodenum, the small intestines, and the large intestines. The secondbody lumen, which is the target of the access, will typically be anorgan or other tissue structure which lies adjacent to thegastrointestinal tract (or may be another part of the GI tract),including the bile duct, the pancreatic duct, the gallbladder, cysts,pseudocysts, abscesses, the pancreas, the liver, the urinary bladder,the duodenum, jejunum, and colon. Particular procedures which maybenefit from the access methods and apparatus of the present inventioninclude gastrojejunostomy, gastroduodenostomy, and gastrocolostomy.Other procedures which can benefit from the methods and apparatus of thepresent invention include vascular bypass including porto systemicshunts and transjugular intrahepatic portasystemic shunt (TIPS)procedures.

The methods and systems of the present invention are advantageous in anumber of ways. For example, by providing an ability to dock a stent oranchor deployment catheter with an endoscope introduced to the firstbody lumen, a very stable platform is provided for sequentiallyaccessing tools to penetrate the luminal walls, maintain the luminalwalls in apposition, and deploy the stent or other anchor while theluminal walls are maintained in apposition. By maintaining asubstantially continuous apposition of the walls at all times after theinitial penetration, the risk of body fluid leakage into body cavitiessurrounding the lumens is minimized. A further advantage provided by themethods and systems herein is the elimination of the need to deploy aguidewire. By deploying a penetrating needle from the stent/anchorplacement catheter to form the initial penetration and subsequentlyintroducing the stent delivery tool(s) over the needle using the samecatheter, the duration of the procedure can be reduced and the need toexchange tools over the guidewire is eliminated. A still furtheradvantage provided by the methods and apparatus of the present inventionis the ability to deploy a tension wire from the needle which isinitially used to penetrate the luminal walls. By deploying an anchor onthe distal end of the tension wire on the luminal wall of the secondbody lumen, tension can be maintained to hold the luminal walls inapposition while the stent/anchor delivery tool is advanced over theneedle.

The stents and anchors which are deployed by the methods and apparatusof the present invention will have distal and proximal flange elementswhich, at the end of the implantation procedure, will engage the luminalwalls and hold the luminal walls together. In addition, the flanges andstent/anchor will seal sufficiently against the luminal walls to inhibitleakage from the time of their initial deployment. Usually, thestent/anchors will include or define a central opening or passage toallow the exchange of fluid between the first body lumen and the secondbody lumen, often being drainage of fluid from the second body lumeninto the first body lumen, e.g., for gallbladder or bile duct drainage.A number of suitable stent/anchors are described in co-pendingapplication US 2009/0281557, the full disclosure of which isincorporated herein by reference.

In a first aspect of the present invention a device is used to deliver atissue stent or anchor in a controlled and predetermined manner. Thecontrolled delivery device is introduced through the working channel ofan endoscope and includes a proximal handle that provides control ofdelivery and a catheter that extends from a distal end of the proximalhandle to the distal end of the device. The handle has a coupling memberfor removable attachment to the endoscope to provide a stable deployableplatform. The catheter includes an outer sheath, at least one shaft(e.g., an inner catheter or pusher tube) that is used to deploy thetissue anchor, and a tapered distal tip. The handle has coaxial slidingelements that control at least three operations, including devicecatheter positioning, distal anchor deployment, and proximal tissueanchor deployment. Such devices and apparatus will typically furtherinclude a first lock and a second lock for securing the first slidingelement and the second sliding element, respectively. The ability tolock the sliding elements allows deployment of other components of theapparatus while maintaining the same relative position of the lockedcomponents.

The shaft and sheath of the catheter of the apparatus will be coaxiallydisposed so that the stent or anchor may be held over the shaft andconstrained by the sheath. Thus, when using a self-expanding stent oranchor, the distal stent or anchor can be deployed by retracting thesheath over the stent or anchor while maintaining constraint of theproximal stent/anchor until deployment is desired. As described in moredetail below, this allows the distal flange to be deployed and used topull back on the wall of the second body lumen to maintain apposition asthe proximal flange is deployed to complete the stent/anchorimplantation.

Usually, the catheter shaft will have an axial passage extendingtherethrough. In some embodiments, the axial passage may be adapted toreceive a guidewire. Usually, however, the catheter will furthercomprise a needle which is slidably disposed in the axial passage of theshaft. The needle will have a tissue penetrating tip, usually beingsharpened, pointed or having an electrosurgical element, and will beoperatively connected to a third slider or actuator on the handle,allowing a user to deploy the needle from the catheter, while thecatheter is attached to the endoscope, in order to initially penetratethe luminal walls. Immediately after penetrating the luminal walls, theshaft and sheath of the catheter may be advanced over the needle to passthrough the penetration in the luminal walls. Usually, the distal tip ofthe shaft will be tapered or have a cutting element to facilitateopening the passage through the luminal walls. The sheath may then berefracted over the shaft, again using the slider on the handle, in orderto deploy the stent/anchor as discussed above.

In a still further specific aspect, the device may include a tensionwire which is slidably disposed in an axial passage of the needle. Thetension wire has an anchor at its distal end which can engage a wall ofthe second body lumen to provide tension as the catheter shaft andsheath are advanced over the needle. Typically, the anchor comprises aself-expanding structure formed integrally with the tension wire,usually comprising a plurality of loops which deploy rearwardly to forma concave structure or the wall of the second body lumen, e.g. where theconcave structure provides clearance for advancing the catheter shaftand sheath past the luminal walls. A particular advantage of the concavestructure is that it will protect against accidental needle penetrationsafter the anchor is deployed.

In a second aspect of the invention, methods for delivering a stent orother luminal anchor from a first body lumen to a second body lumencomprise advancing an endoscope having a working channel through thefirst body lumen to a target site on a wall of the first lumen. A stentdeployment catheter is advanced through the working channel of theendoscope, and a handle control mechanism on the stent deploymentcatheter is attached to the endoscope so that the handle is immobilizedrelative to said endoscope. The stent deployment catheter assemblyincludes a shaft, a self-expanding stent (or anchor structure) carriedon the shaft, and a sheath constraining the stent on the shaft, and thehandle is used to sequentially manipulate the various cathetercomponents in order to deploy the stent. Usually, the catheter assemblyis advanced from the first body lumen, through the apposed walls at thetarget site and into the second body lumen through a passage in theluminal walls. After positioning the catheter, the sheath is retractedrelative to the endoscope handle and shaft by a distance sufficient torelease a distal portion of the stent to form a distal flange. The stentdeployment assembly may then be pulled proximally, typically usingcontrols on the handle, to engage the distal flange against the wall ofthe second body lumen to draw the two luminal walls into closerapposition. The sheath is then further retracted relative to theendoscope, handle and shaft to release the remaining portion of thestent to deploy a proximal flange against the wall of the first bodylumen.

In some embodiments, the passage through which the stent deploymentcatheter is advanced may be pre-formed with separate tool(s), forexample using trocars or other instruments as described in co-pendingapplication Ser. No. 12/757,408, the full disclosure of which isincorporated herein by reference. More usually, however, the passagethrough the luminal walls will be formed by advancing a needle carriedby the stent deployment catheter relative to the handle and endoscope topenetrate the needle through the apposed luminal walls. When using the“on-board” needle, the stent deployment catheter may then be advancedover the needle and through the apposed walls after the needle haspenetrated the apposed walls. Preferably, tension will be applied to theapposed walls while the stent deployment catheter is advanced, typicallyby positioning an anchor on a tension wire on the luminal wall of thesecond body lumen. In the exemplary embodiments, the tension wire isdeployed through an axial passage in the needle. Applying tensionreduces the chance of accidental leakage of body fluids during the stentdeployment. Alternatively, tension could be applied using separatelydeployed T-tags or other tethers.

In this specific embodiment, the stent deployment catheter is advancedby manually advancing a catheter slider on the handle, where thecatheter slider is coupled to the catheter assembly to move the shaft,sheath, and stent in unison relative to the handle and endoscope.Similarly, retracting the sheath will comprise manually retracting asecond slider on the handle, typically a collar on the catheter slider,where the second slider is coupled to the sheath to move the sheathrelative to the shaft, the stent, handle, and endoscope. Thirdly,advancing the needle will typically comprise manually advancing a needleslider on the handle, where the needle slider is coupled to said needleto move the needle (which optionally carries the tension wire) relativeto the shaft, stent, handle, and endoscope. In contrast, the tensionwire and anchor are typically deployed by direct manual movement of aproximal end of the wire which extends through the central passage ofthe needle and out of the proximal end of the handle.

In a third aspect of the present invention, a catheter for delivering aself-expanding stent through apposed luminal walls comprises a shaft, aneedle, a tension wire, a self-expanding stent, and a retractablesheath. The shaft has a distal end, a proximal end, and an axial passagetherethrough. The needle is slidably positioned in the axial passage ofthe shaft and has a tissue-penetrating distal tip that can be advanceddistally beyond the distal end of the shaft and retracted proximallywithin the passage of the shaft. The needle also has an axial passagetherethrough, and the tension wire is slidably positioned in the axialpassage of the needle. The tension wire includes a deployable anchor atits distal end where the anchor can be distally advanced beyond thedistal tip of the needle and proximally retracted into the axial passageof the needle. The self-expanding stent is carried coaxially over theshaft and is constrained by the retractable sheath which is disposedthereover, as well as over the shaft. By proximally retracting thesheath, the stent can be released from constraint to deploy across theluminal walls.

The catheter typically further comprises a handle having a body with acoupling member that can be removably secured to a proximal end of anendoscope to position the catheter shaft within a working channel of theendoscope. The handle usually includes a catheter slide actuator toselectively advance and retract the catheter shaft within the workingchannel of the endoscope while the handle is secured to the endoscope.The handle usually also includes a second slide actuator, typically acollar on the catheter slide actuator, to selectively advance andretract the sheath over the shaft to release the self-expanding sheathfrom constraint. Additionally, a needle slide actuator is usuallyprovided to selectively advance and retract the needle relative to theshaft.

The anchor on the tension wire may have a variety of configurations, butwill usually be a self-expanding structure formed integrally with thetension wire. In this specific example, the self-expanding structurecomprises a plurality of loops which deploy rearwardly to form a concavestructure over the wall of the second body lumen, where the concavestructure provides clearance for advancing the shaft and sheath throughthe luminal walls and protects the needle tip to inhibit accidentalpunctures.

The catheter may further comprise a port disposed on or otherwisecoupled to a proximal end of the needle. The port may be used foraspiration and/or perfusion through the axial passage of the needle. Forexample, the port can allow for detection of when the needle has beenadvanced into the second body lumen as fluid from the second lumen maybe aspirated through the port.

In the fourth aspect, the present invention provides methods fordelivering a stent or other luminal anchor from the first body lumen,through apposed luminal walls, to a second body lumen. The methodcomprises positioning an endoscope in the first body lumen adjacent to atarget site on a luminal wall. A catheter assembly is advanced through aworking channel of the endoscope to locate a distal region of thecatheter assembly at the target site. A needle carried by the catheterassembly may then be penetrated through the apposed walls at the targetsite, and an anchor on the distal end of a tension wire deployed in thesecond body lumen, typically from an axial passage within the needle. Bydrawing proximally on the tension wire (usually together with theneedle), tension may be maintained on the walls to maintain the walls inclose apposition to inhibit leakage of body fluids. A stent deploymentsub-assembly which carries the stent is then advanced over the needlewhile maintaining tension on the tension wire. A distal flange on thestent may be expanded in the second body lumen, and the stent deploymentsub-assembly drawn proximally to pull the distal flange against the wallof the second body lumen to maintain the walls in apposition, allowingthe anchor on the tension wire to be withdrawn. While maintaining thewalls in apposition with the distal flange, the proximal flange on thestent may be expanded in the lumen to complete the implantation. Thecatheter may then be withdrawn from the body lumens.

In particular instances, the anchor may be deployed by advancing thetension wire through an axial passage of the needle after the needle haspenetrated through the apposed walls. The anchor will usually beself-expanding and be formed integrally with the tension wire. Thus, theself-expanding anchor will deploy as the tension wire is advanced fromthe needle allowing the anchor to be released from the constraint of theaxial passage of the needle. In specific examples, the self-expandingstructure comprises a plurality of loops which deploy rearwardly to forma concave structure over the wall of the second body lumen, where theconcave structure provides clearance for advancing the stent deploymentsub-assembly across the walls.

In most embodiments, the stent will also be self-expanding and bedeployed by retracting a sheath which is part of the stent deploymentsub-assembly. Usually, the sheath will be sequentially retracted tofirst deploy the distal flange and, after drawing the distal flangeagainst the wall of the second body lumen, the sheath may be furtherretracted to deploy the proximal flange and complete implantation of thestent across the luminal walls.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a first embodiment of a stent deployment apparatusconstructed in accordance with the principles of the present invention.

FIG. 2 is a cross-sectional view of the distal end of the stentdeployment apparatus of FIG. 1, taken along line 2-2 of FIG. 1.

FIGS. 3A-3E illustrate use of the stent deployment apparatus of FIG. 1for deploying a stent through apposed luminal walls according to theprinciples of the methods of the present invention.

FIG. 4 illustrates a second embodiment of the stent deployment apparatusof the present invention.

FIGS. 5A-5E illustrate sequential actuation of the various tools of thestent deployment apparatus of FIG. 4.

FIGS. 6A-6G illustrate use of the apparatus of FIG. 4 for deploying astent across apposed luminal walls in accordance with the principles ofthe methods of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The device 10 of FIG. 1 includes a control handle 12 having a body 14with a first slide actuator 15 with knob 16 and lock 20. A second slideactuator 18 with lock 22, scope locking mechanism 24, catheter body 26,a sheath 27, shaft 28, stent lock 30, distal tapered tip 32 and stent orother tissue anchor 34 (FIG. 2).

The distal end of endoscope or echo-endoscope 40 (FIG. 3A-3E) ispositioned usually via trans-oral entry adjacent to a target locationwithin the GI tract. A puncture is made at the desired location using a19 gauge needle (typically an electrosurgical needle) followed byplacement of a guidewire 102 through the needle lumen and optionalballoon dilation over the guidewire or by using an expanding trocar asdescribed in co-pending application Ser. No. 12/757,408, filed on Apr.9, 2010, the full disclosure of which was previously incorporated hereinby reference.

The catheter body 26 is then advanced over the guidewire 102 through theworking channel of the endoscope 40 and is secured to the proximal endof a working channel using scope locking mechanism 24 to locate thecatheter body 26 with a tip 32 approximately 1 cm outside of the distalend of the working channel, as in FIG. 3A.

The first slide actuator 15 is distally advanced using knob 16, afterreleasing lock 20, on handle 12, thus moving the assembly of catheterbody 26, shaft 28, and stent 34, in the distal direction and through thetract formed through tissue T1 and tissue T2 and moving distal taperedtip 32 from lumen L1 to lumen L2 as in FIG. 3B. Lock 20 is thenreengaged, securing first slide actuator 15 to control handle body 14.

A distal flange segment 42 of the tissue anchor 34 is now expanded bymoving the second slide actuator 18 in the proximal direction to retractsheath 27. The second slide actuator is pulled back to a predeterminedposition part way along the proximal extension 17 of the first slideactuator 15, after releasing second lock 22 as in FIG. 3C. A portion oflock 22 (FIG. 1) of second slide actuator 18 moves in a track (notshown), where said lock 22 engages a stop at a predetermined position,thereby stopping the proximal movement of actuator 18. Saidpredetermined position is calibrated to allow only the distal flange 42of tissue anchor 34 to be released from constraint by sheath 27 and toexpand. Said proximal motion of second slide actuator 18 retracts thesheath 27, while the shaft 28 is held in place, this releasing thedistal portion of tissue anchor 34 from constraint.

The first slide actuator 15 is now moved slowly in the proximaldirection using knob 16, after releasing lock 20, on handle 12, thusmoving the expanded distal anchor flange 42 against the inner surface oftissue T2 of lumen L2, and positioning tissue T1 closer to tissue T2,holding lumen L1 and L2 in close apposition as in FIG. 3D. Stent lock 30(FIG. 2) holds the proximal end of the tissue/stent anchor 34 firmlyallowing proximal traction against tissue T2. Lock 20 is then reengaged,securing first slide actuator 15 to control handle body 14.

A proximal segment 44 of the tissue anchor stent 34 is now expanded bymoving the second slide actuator 18 in the proximal direction to aposition at or near the proximal end of the first slide actuator 15,after releasing lock 22 as in FIG. 3E to further retract the sheath 27.The proximal end of the tissue anchor stent 34 releases from stent lock30 (FIG. 2) as the second slide actuator 18 reaches the proximal end ofits travel. This releases the entire tissue anchor, which in thisexample has a central lumen 46 allowing fluid communication betweenlumens L1 and L2. The device 10 is now removed, leaving the tissueanchor 34 with central lumen 46 implanted between lumen L1 and lumen L2with fluid communication being established.

Of particular interest in advanced therapeutic endoscopy is the drainageof bile from the gallbladder into the duodenum or stomach. This isaccomplished endoscopically from within the GI lumen of the duodenum orstomach and requires that the gallbladder be located using transluminalimaging, such as endoscopic ultrasound (EUS), followed by penetrationthrough the GI lumen and gallbladder wall and precise placement of adrainage stent between these structures. During the placement of thedrainage stent, it is necessary that close apposition of the gallbladderand GI lumen be maintained to prevent bile leakage into the peritonealcavity, a situation that can cause peritonitis which can be fatal. Inthis instance, delivery of a tissue anchor or luminal approximatingstent requires precise control allowing that close apposition ismaintained throughout the procedure and throughout the course oftherapy. Using the devices of the present invention tissue stents andanchors, such as those described above or in co-pending application US2009/0281557, can be precisely delivered.

An alternative embodiment of the stent deployment system of the presentinvention is illustrated in FIGS. 4 and 5A-5E. This alternative systemis specifically designed for direct delivery and implantation of thestent or other anchor without use of a guidewire and allows themanipulation of all components of the system to form a single handlewhile the handle is secured to an endoscope used to access the firstbody lumen to provide a stable implant delivery platform. The componentsof the system have been optimized to minimize the risk of body fluidleakage during the stent or anchor implantation procedure, particularlyenhancing the seal maintained on the penetration through the wall of thesecond body lumen to reduce leakage from that lumen.

As shown in FIG. 4, the alternative stent delivery system 100 comprisesa catheter 102 attached at its proximal end to a distal end of a handleassembly 104. The catheter 102 includes a plurality of coaxiallydisposed components as best seen in FIGS. 5A-5E. A catheter shaft 106extends the entire length of the catheter (a portion of the distal endis broken away to show internal components) and is attached at itsdistal end to a tapered tip 108 which includes a leading end 110 usuallyhas includes a cutting edge or element to cut tissue as the tip isadvanced therethrough. A needle 112 having a tissue-penetrating tip 114is slidably received within an axial passage of the shaft 106 so thatthe needle can be extended distally beyond the distal end of thecatheter, as shown in FIG. 5B, even when all other components aremaintained within the catheter. A tension wire 116 is slidably disposedwithin an axial passage of the needle 112 and includes an anchorstructure 118 which can be deployed when it is extended distally beyondthe tip 114 of the needle 112, as illustrated in FIG. 5C. The entirecatheter 102 (distal to the handle 104) is covered by a retractablesheath 120, and the sheath maintains radial constraint on aself-expanding stent 122 or other anchor, allowing deployment of thestent by refraction of the sheath, as shown in FIG. 5E. The catheter 102is shown in its initial delivery configuration in FIG. 5A where allsystem components are retracted within the sheath, with the needle 112retracted within the shaft 106, and the tension wire 116 retractedwithin the needle. In FIG. 5A, the needle 112 is shown distally extendedbeyond the distal end of the remaining components in the catheter 102.In FIG. 5C, the anchor structure 118 of the tension wire 116 is showndistally extended beyond the distal tip 114 of the needle. In FIG. 5D,the sheath 120 is shown retracted relative to the shaft so that at leastthe cutting edge 110 of the tapered tip 108 is exposed beyond the distalend of the sheath 120. Finally, in FIG. 5E, the catheter 102 is shownwith all components fully extended (except for the sheath 120 which isretracted) and with the stent 122 shown in its radially expandedconfiguration having a proximal flange 124 and a distal flange 122.

The handle assembly 104 comprises a plurality of slide actuators whichpermit selective advancement and retraction of the various components ofthe catheter 102, as will now be described. The handle assembly 104includes a body 130 having a coupling member 132 at its distal end. Thecoupling member 132 is selectively attachable to the proximal hub of anendoscope E (as shown in FIG. 6A) after the catheter 102 has beenintroduced through the working channel. From that point on in anyprocedure, the body 130 of the handle assembly 104 will remain fixedrelative to the endoscope while the remaining components in the handlemay be selectively advanced and retracted in order to deploy the variouscomponents of the catheter. In particular, a first tubular slider 134 iscoupled to advance the needle and tension wire when it is pushed forwardrelative to the body 130. A second tubular slider 136 is coupled to thecatheter shaft and sheath in order to advance the shaft and sheath inunison when the slider 136 is pushed forward relative to the body 130.The first and second tubular sliders 134 and 136, however, are decoupledso that manipulation of the first tubular slider does not affect theposition of the shaft and sheath while manipulation of the secondtubular slider 136 does not affect the position of the needle andtension wire.

The sheath may be retracted relative to the shaft and other systemcomponents using a collar 138 which is slidably disposed over the secondtubular slider 136. Refraction of the collar 138 retracts the sheath butleaves all other system components stationary relative to the body 130and endoscope to which it is attached. A proximal handle 140 at theproximal end of the tension wire 116 extends out from a Touhy Borstfitting 142 when a Y-connector 144 attached to the proximal end of theneedle 112. The Y-connector 144 also includes an aspiration/infusionport 146 which is fluidly coupled to the central passage of the needle.The tension wire 140 may be advanced and retracted relative to all othersystem components by loosening the Touhy Borst fitting and manuallyadvancing or retracting the handle 140.

By manually advancing the tension wire 116 using the handle 140, theanchor structure 118 is deployed. Usually, the anchor structure 118 ispre-shaped to assume a desired configuration when it is released fromthe confinement of the needle lumen. Conveniently, the anchor structureand the entire tension wire may be formed from Nitinol or othershape-memory alloy. In the exemplary elements, the anchor structure 118comprises a plurality of loops which deploy rearwardly to form a concavestructure (with the concave surface in the rearward or proximaldirection), as illustrated in FIGS. 5C-5E. The structure may be formedfrom a single length of the wire which folds back on itself to form theillustrated structure. Alternatively, the wire could be split to formthe multi-loop structure from a single larger loop. A variety of othergeometries and structures could be provided for the anchor structure,including cones, conical spirals, multiple everting elements, and thelike.

A detailed construction for the catheter handle showing the connectionsbetween the handle components and the catheter components is provided inAppendix A attached to this application.

Referring now to FIGS. 6A-6G, the stent deployment system 100 isillustrated in use for implanting stent 122 between tissue layers T1 andT2 and body lumens L1 and L2. Body lumen L2 has a back wall T3 which isto be protected during the procedure. As shown in FIG. 6A, an endoscopeE is positioned within the body lumen L1, and the distal end of thecatheter 102 is advanced through a working channel of the endoscope tobe positioned adjacent to a target location TL on the luminal wall T1 ofbody lumen L1. Usually, visualization using the endoscope will besufficient to properly locate the target location, but use offluoroscopy, endoscopic ultrasound, or other imaging modes would also bepossible.

After the target location TL has been identified, the needle 112 will beadvanced through the target location on T1 and through a correspondinglocation on T2, as shown in FIG. 6B. The endoscope is not shown in FIGS.6B-6G, but it would still be present as the catheter handle assembly 104would have been connected to a proximal hub on the endoscope prior toneedle advancement. The needle will be advanced by distally advancingthe first tubular slider 134. Successful entry into the lumen L2 can beconfirmed by aspirating fluid through the needle lumen and port 146 onthe Y-connector 144. Usually, a lock or a limiter (not shown) will beprovided on the handle assembly 104 so that forward advancement of thefirst tubular slider 134 is stopped at a depth which preventspenetration through the back wall T3 of the lumen L2.

Once the needle 112 has successfully reached the interior of body lumenL2, the anchor structure 118 will be deployed, as shown in FIG. 6C.Deployment is conveniently achieved by advancing handle 140 at theproximal end of the tension wire 116 to deploy the multi-lobed structureas described previously.

Once the anchor structure 118 has been successfully deployed, the needle112 and tension wire 116 may be retracted relative to the remainingcomponents of the catheter and the endoscope in order to draw the anchor118 proximally to close the tissue walls T1 and T2 closer together, asalso shown in FIG. 6C.

After the tissue walls T1 and T2 are drawn into closer apposition, thetapered tip 114 of the catheter 102 may be exposed by partiallyretracting the sheath 120, as shown in FIG. 6D, and the catheteradvanced through the needle penetration with the tapered tip (usuallyincluding a cutting element) facilitating advancement and enlarging thepenetration. Continued tension on the needle 112 and tension wire 116help maintain apposition between tissue layers T1 and T2 duringadvancement of the catheter to reduce the risk of body fluid leakagefrom either body lumen, particularly from the target lumen L2.

Once the catheter 102 has successfully entered second body lumen L2, asshown in FIG. 6E, the proximal flange 124 of the stent 122 may bedeployed by further retracting the sheath 120 and the needle 112 andanchor structure 118 can be withdrawn. The proximal flange may then bedrawn proximally against the wall of T2, as shown in FIG. 6F toreestablish apposition of the luminal walls during the remainder of thedeployment procedure. The flange 124 may be retracted using the secondtubular slider 136 which is coupled to the shaft which carries thestent. A stent lock (not shown) or other structure is provided toprevent the stent from sliding over the shaft during the deploymentprocedure prior to full expansion of the stent. After the tension hasbeen applied using the distal flange 124, the sheath 120 may be furtherretracted, using sheath collar 138, to fully deploy the stent so thatthe proximal flange 122 engages a luminal surface of the first tissuelayer T1, as shown in FIG. 6G. After the stent is deployed, the catheterincluding all components may be removed by detaching the handle from theendoscope and withdrawing the entire structure. A central passage oropening through the stent provides for a fluid communication betweenlumens L1 and L2, typically for drainage of fluids from second bodylumen L2 into the first body lumen L1.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention which is defined by the appendedclaims

1. A method for delivering a stent from a first body lumen, throughadjacent opposing luminal walls, to a second body lumen to form ananastomosis, said method comprising: advancing an endoscope having aworking channel to a target site on a wall of the first lumen; providinga stent deployment apparatus having a control handle and a stentdeployment catheter assembly; advancing at least a portion of the stentdeployment catheter assembly into the working channel of the endoscope;attaching the control handle to the endoscope so that the control handleis immobilized relative to the endoscope; advancing the stent deploymentcatheter assembly including a shaft, a self-expanding stent carried onthe shaft, and a sheath constraining the stent on the shaft relative tothe control handle and the endoscope and through a passage from thefirst body lumen, through the opposing walls at the target site, andinto the second body lumen; retracting the sheath relative to theendoscope, control handle and shaft by a distance sufficient to releasea distal portion of the stent and form a distal flange; pullingproximally on the stent deployment catheter assembly such that theshaft, the stent and the sheath move simultaneously in the proximaldirection to engage the distal flange against the wall of the secondbody lumen to draw the two luminal walls into closer apposition while aproximal flange of the stent remains constrained by the sheath; andfurther retracting the sheath relative to the endoscope, control handle,and shaft to release portions of the stent remaining constrained by thesheath, wherein the proximal flange expands against the wall of thefirst body lumen.
 2. A method as in claim 1, wherein the passage waspre-formed before advancing the stent deployment catheter.
 3. A methodas in claim 1, further comprising forming the passage by advancing aneedle carried by the stent deployment catheter relative to the controlhandle and the endoscope to penetrate the needle through the opposingwalls.
 4. A method as in claim 3, wherein the stent deployment catheteris advanced over the needle through the opposing walls after the needlehas penetrated said opposing walls.
 5. A method as in claim 4, furthercomprising applying tension to a tension wire which has an anchor in thesecond body lumen while the stent deployment catheter is advanced overthe needle.
 6. A method as in claim 5, wherein the tension wire isdeployed through an axial passage in the needle.
 7. A method as in claim1, wherein advancing the stent deployment catheter comprises manuallyadvancing a catheter slider on the control handle, wherein the catheterslider is coupled to said catheter assembly to move the shaft, thesheath, and the stent in unison relative to the control handle andendoscope.
 8. A method as in claim 7, wherein retracting the sheathcomprises manually retracting a collar slider on the control handle,wherein the collar slider is coupled to said sheath to move the sheathrelative to the shaft, the stent, the control handle and the endoscope.9. A method as in claim 3, wherein advancing the needle comprisesmanually advancing a needle slider on the control handle, wherein theneedle slider is coupled to said needle to move said needle relative tothe shaft, the stent, the control handle and the endoscope.
 10. A methodas in claim 1, wherein the first body lumen is selected from the groupconsisting of the esophagus, the stomach, the duodenum, the smallintestines, and the large intestines and the second body lumen isselected from the bile duct, the pancreatic duct, the gallbladder,cysts, pseudocysts, abscesses, the pancreas, the liver, the urinarybladder, duodenum, jejunum, and colon.
 11. A method as in claim 1,further comprising a step of locking a proximally pulled position of thedeployment catheter assembly relative to the control handle and theendoscope after the step of pulling proximally on the deploymentcatheter assembly but before the step of further retracting the sheath.